With the advent of digital cameras and photographing cell phones, people can better capture pictures and share photos. Current technology enables pictures to be easily and conveniently previewed, taken, and reviewed. Digital photography has made cameras compact, portable, and low-powered. However, certain trade-offs are often associated with the portability that miniaturization brings, somewhat undermining the benefits of a readily accessible form of image-capture and picture quality.
A prime lens has a fixed focal length, so a user must adjust his or her relative position to get a desired image. This can impede the capture of an image if there is not enough physical space to properly frame the desired image. A zoom lens is versatile, can be adapted to different photo-taking environments, and is more flexible than the prime lens in term of view finding. When using a zoom lens, a user is able to transition from a wide-angle view to a telephoto view with a single zoom lens without the need to physically move and thus capture alternative views. However, such flexibility is usually at the expense of compromising picture quality, and the image quality from a zoom lens is usually poorer than that from a prime lens. The aperture of a zoom lens is usually smaller than a prime lens, so a zoom lens has less entered light than a prime lens. In addition, a zoom lens usually has more pieces of lenses than a prime lens, which results in scattering and intensity decreasing of the light passing more pieces of lenses. A prime lens preserves the integrity of an image by virtue of its simple design. A prime lens has one focal length and fewer moving parts and lenses than a zoom lens, which yields accuracy of the mechanism and sharper images.
Additionally, for a camera module to provide zoom lens capability, the internal construction of the lens is rather complicated. A zoom lens may generally have over hundreds of individual parts. One poorly machined part may squander the financial investment in the zoom lens, whether at the manufacturing stage or the commercial stage. Also, zoom lenses usually tend to be bulky and heavy, making them infeasible where portability is paramount.
Prime (or fixed focal length) camera lenses typically provide higher quality images than zoom or variable focal length lenses. Prime lenses also usually tend to be more compact and light weight than zoom lenses. In many modern imaging devices, particularly mobile phones, compactness is of utmost importance, making zoom lenses somewhat impractical. Therefore, most mobile devices do not have zoom function.